Skip to main content

Lake Pontchartrain Causeway - Exploring the "World's Longest Bridge"


One of the great engineering achievements of southeast Louisiana – a region of the country that is no stranger to impressive feats of engineering – is the Lake Pontchartrain Causeway, or “The Causeway” as its often referred to, spanning the Lake between suburban Jefferson Parish outside New Orleans and the north shore community of Mandeville. At a length of 23.9 miles from end to end, it is one of the longest bridges in the world – long enough to be classified in the Guinness Book of World Records as the “longest continuous bridge over water in the world” as of January 2024.

The idea for the modern Causeway was conceived in the years after World War II, when the New Orleans metro area grew quickly as the suburban development of Jefferson Parish threatened to spill over into the neighboring parishes. The Greater New Orleans Expressway Commission (also known as the Causeway Commission) was established in 1948 with the goal of planning and constructing the cross-lake bridge. Construction of the initial two-lane bridge took place from 1953-1956 at a cost of $46 million, including improvements to Causeway Boulevard in Metairie and Mandeville.

The above satellite view shows the greater New Orleans metro area to the bottom of the photo. Lake Pontchartrain, and the Causeway that crosses it, are visible at the center.

The Causeway proved to be a huge success from the beginning. In fact, in some ways it became a victim of its own success, with traffic counts soon proving to be too great for the two-lane bridge to safely handle. In response, planning for the parallel span took place in the early 1960s, with the new span opening in 1969 at a cost of $30 million. Since the completion of the parallel span, southbound traffic crosses on the original bridge, while northbound traffic crosses on the second bridge. While lying mostly level with the lake for its entirety, there are multiple raised navigation spans along the way for taller recreational boating traffic to pass safely under the bridges. A high-level bascule draw span stands near Milepost 17, about 8 miles south of the Mandeville shoreline, enabling larger commercial craft to pass the bridge. (On the Causeway, the mileposts begin with "0" located at the Metairie shoreline.)

These photos from November 2023 are taken from the Metairie shoreline and show how the Causeway starts out over the lake and disappears over the horizon. (Click on each photo to view a larger version.)

The Causeway is operated as a toll bridge. As of January 2024, the cost is $6 for passenger cars, collected in the southbound direction at a toll plaza on the Mandeville approach to the bridge. Tolls were originally collected in both directions, however northbound toll collection ceased in 1999 and the original northbound toll plaza located at the end of Causeway Boulevard in Metairie was removed. The frequent traffic jams caused by the toll plaza that often spilled over onto Causeway Boulevard and the nearby intersection thoroughfares played a role in this decision. In any case, the Causeway is one of the only tolled facilities in the state of Louisiana. The tolls provide revenue that helps maintain the bridges as well as fund improvement projects. The most significant of these took place in 2019, when a $53 project saw the addition of emergency pull off areas to the bridge in both directions. A separate project carried out later that year saw the replacement and improvement of the railings and parapet barriers along the length of the southbound bridge. All the measures taken lately have significantly improved safety along the Causeway as traffic counts are now as high as they have ever been.

The immense proportions of the Causeway's length can be appreciated the most from the air. These 2017 photos of the Causeway were taken by yours truly as an airplane passenger above Lake Pontchartrain. (Click on each photo to view a larger version.)

I’ve had the opportunity to drive the Causeway on multiple occasions over the years. My first visit to the crossing came in January 2017 as part of my initial visit to southeast Louisiana. In February 2023, I revisited the Causeway and got to experience a round-trip crossing on the bridge a second time. Crossing this bridge is one of those unique experiences that is both enjoyable and unpredictable at the same time. At a point about 10 miles into the crossing, land in all directions disappears from sight and one has the feeling of being isolated from civilization for a period of time. In the southbound direction, it’s often the case that the first signs of land to appear on the horizon are the skyscrapers of downtown New Orleans off to the southeast (including the roof of the Superdome) and the looming structure of the Lakeway Center located on Causeway Boulevard directly ahead.

Above: The skyline of New Orleans comes into view about 15 miles to the southeast as one travels southbound on the Causeway.

At a length of 24 miles from end to end, it’s one of the longest stretches of highway in America without any interchanges or ways to divert to an alternate route in the event of trouble. Weather conditions often change rapidly over the lake, meaning that the conditions that one encounters when setting off on the Causeway can sometimes be very different only a few miles later. In the winter months, dense fog is not uncommon over parts of the lake, meaning the visibility can drop rather abruptly with little warning. In the summer months, the trademark Louisiana thunderstorms can form quickly over the lake and drift over the Causeway, causing hazardous conditions on a moment’s notice. The variable weather conditions that can be experienced on any given day, plus the typical risks for vehicle-related incidents on a bridge of this length, combine to make for an exciting trip that always requires driver attention due to potential unforeseen factors.

The following images from February 2023 chronicle the crossing of the Causeway northbound, from Metairie to Mandeville. Click on each photo to see a larger version.

The following images from February 2023 chronicle the crossing of the Causeway southbound, from Mandeville to Metairie. Click on each photo to see a larger version.

Dashcam video of the northbound drive over the Causeway was filmed in February 2023 for the 'roadwaywiz' YouTube channel and is available for viewing at the link below:

Dashcam video of the southbound drive over the Causeway was filmed in February 2023 for the 'roadwaywiz' YouTube channel and is available for viewing at the link below:

How To Get There:


Popular posts from this blog

Horace Wilkinson Bridge (Baton Rouge, LA)

Standing tall across from downtown Baton Rouge, the Horace Wilkinson Bridge carries Interstate 10 across the lower Mississippi River between West Baton Rouge and East Baton Rouge Parishes. Unusually, the bridge is actually named for three separate people; three generations of Horace Wilkinsons who served in the Louisiana State Legislature over a combined period of 54 years. Constructed in the 1960s and opened to traffic in 1968, this is one of the largest steel bridges on the lower Mississippi. It’s also the tallest bridge across the Mississippi, with its roadway reaching 175 ft at the center span. Baton Rouge is the northernmost city on the river where deep-water, ocean-going vessels can operate. As a result, this bridge is the northernmost bridge on the river of truly gigantic proportions. Altogether, the bridge is nearly 2 ½ miles long and its massive truss superstructure is 4,550 ft long with a center main truss span of 1,235 ft. The Horace Wilkinson Bridge is one of the largest

Sunshine Bridge (Donaldsonville, LA)

Located about halfway between Baton Rouge and New Orleans in southern Louisiana, the Sunshine Bridge spans the lower Mississippi River near the city of Donaldsonville as part of the longer Louisiana Highway 70 corridor, which connects Interstate 10 and Airline Highway (US 61) with US 90 in Morgan City. In the years following World War II, the only bridges across the lower Mississippi River in Louisiana were located in the area of the state’s two largest cities – Baton Rouge and New Orleans. Postwar agricultural and industrial development along the river in this region led to the planning of a series of infrastructure projects in southern Louisiana that were aimed at spurring this development and modernization of the Delta region. One of these projects was known as the Acadian Thruway and was developed in the 1950s as a toll road intended to connect greater New Orleans with Lafayette and points west while providing a high-speed bypass of the Baton Rouge metro area. The Thruway, which

Natchez-Vidalia Bridge (Natchez, MS)

  Located about halfway between Baton Rouge and Vicksburg near the city of Natchez, the Natchez-Vidalia Bridge crosses the lower Mississippi River between southwest Mississippi and northeastern Louisiana at the city of Vidalia. This river crossing is a dual span, which creates an interesting visual effect that is atypical on the Mississippi River in general. Construction on the original bridge took place in the late 1930s in conjunction with a much larger parallel effort by the U.S. Army Corps of Engineers to strengthen the area’s flood protection and levee system along the Mississippi River. One of the more ambitious aspects of this plan was to relocate the city of Vidalia to a location of higher ground about one mile downriver from the original settlement. The redirection of the river through the Natchez Gorge (which necessitated the relocation of the town) and the reconstruction of the river’s levee system in the area were undertaken in the aftermath of the Great Flood of 1927, wh